TS-4900 LEDs: Difference between revisions
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The kernel provides various triggers that can be useful for debugging purposes: | The kernel provides various triggers that can be useful for debugging purposes. The trigger for a given LED is in its directory: | ||
<source lang=bash> | |||
echo "heartbeat" > /sys/class/leds/red-led/trigger | |||
</source> | |||
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| Toggle on Camera activation. Not currently used. | | Toggle on Camera activation. Not currently used. | ||
|} | |} | ||
<References /> | |||
Revision as of 14:46, 14 July 2014
The kernel provides access to control the LEDs using the sysfs:
# Set Red led on
echo 1 > /sys/class/leds/red-led/brightness
# Set Red led off
echo 0 > /sys/class/leds/red-led/brightness
# Set Green led on
echo 1 > /sys/class/leds/green-led/brightness
# Set Green led off
echo 0 > /sys/class/leds/green-led/brightness
The kernel provides various triggers that can be useful for debugging purposes. The trigger for a given LED is in its directory:
echo "heartbeat" > /sys/class/leds/red-led/trigger
| Trigger value | |
|---|---|
| none | Default, no action |
| mmc0 | MicroSD card activity |
| mmc1 | eMMC activity |
| mmc2 | WIFI SDIO activity |
| timer | 2hz blink |
| oneshot | Blinks after delay. [1] |
| heartbeat | Similar to timer, but varies the period based on system load |
| backlight | Toggles on FB_BLANK |
| gpio | Toggle based on a specified gpio. [2] |
| cpu0 | Blink on CPU core 0 activity |
| cpu1 | Blink on CPU core 1 activity |
| cpu2 | Blink on CPU core 2 activity |
| cpu3 | Blink on CPU core 3 activity |
| default-on | Only turns on by default. Only useful for device tree. |
| transient | Specify on/off with time to turn off. [3] |
| flash/torch | Toggle on Camera activation. Not currently used. |
- ↑ See the Kernel documentation for more details
- ↑ When this trigger is set, a "gpio" file appears in the same directory which can be used to specify what GPIO to follow when it blinks
- ↑ See the Kernel documentation for more details